ci: added install of dev requirements

.gitlab-ci.yml

@@ -13,6 +13,7 @@ test:
     - python3 setup.py install
     - pip3 install -r requirements.txt
     - pip3 install -r requirements-test.txt
+    - pip3 install -r requirements-dev.txt
     - flake8
     - mypy .
     - pytest --cov harvester --cov-report term-missing